The Study On Cadmium Induced Apoptosis Of Mouse Granulosa Cells And Interrelated Genes Expression

Cadmium is a contamination of environment and industry. It has obvious toxicity for the reproductive system of female mammalian, which could cause the ovary tissue pathological change, disturbed ovulation and fecundation, lead to sterility provisional, both of the accepters of estrogen and progesterone were affected by cadmium, and the expression of genes as well.Research Aim: The effect of cadmium on the ovarian granulosa cells was defecated and the mechanism was clarified. The theory of cadmium-induced the toxicity on gonad was renewed. The theoretic evidence was provided for later study.Research Methods: Prepubertal female mice as object injected with several dose cadmium chloride after subcutaneous injected with PMSG withdrawal 48 hours. The follicular atresia was detected by pathological method, the apoptosis of granulosa cells were detected by TUNEL and agarose gel electrophoresis; the expression of bax and bcl-2 gene were detected by immunohistochemical, the antagonistic effect of selenium to cadmium was discussed by selenite natrium.Research Results: There is DNA ladder in 96-hours' high-dose group (4mg/kg-wb) by agarose gel electrophoresis, there are no DNA ladder in 48-hours' groups. The results showed that the apoptosis percent of granulosa cells in high, midst , low-dose groups and Se-group are 13.89%,10.76%,10.02%,5.7232% respectively after 48 hours, which are higher than control group significantly(0.6378%, P<0.01).Apoptosis percent of GCs rise obviously in 96-hours' control group( 11.0963%).the high, midst , low-dose groups and Se-group are 20.3204%,12.2031%,12.2171%,14.9203% respectively after 96 hours. There is a significant difference between high-dose group and others, but midst and low-dose groups are similar with control group. The result showed that the apoptosis in diverse degree were occurred in every groups, the apoptosis index increase with dosage rising, there is extreme significant difference (P<0.01). The percent of atresic follicular increase with dosage rising (P<0.05).The result of expression of Bax and Bcl-2 showed that the Bax expressed widely in every groups, and it enhanced with dosage, there is extreme significant difference between experiment group and control group (P<0.01),there is not difference between withdrawal 48 hours and 96 hours. The expression of Bcl-2 was weak or negative; there is no difference among various groups.Research Conclusion: l)Cadmium can accelerate the apoptosis of GCs and is related with dose; 2)Cadmium accelerate atresic of follicular; and increase the number of interstitial gland;3)Cadmium enhance the expression of bax, and no affect obviously on bcl-2;4) Selenium restrained the effect of cadmium-induced apoptosis on granulosa cells, but it can't be interdicted completely.